Normal A1C Levels: What's a Healthy Range?
Understanding your A1C results is key to managing your blood sugar. Learn what's normal, what indicates prediabetes, and when A1C levels signal diabetes.
Your blood sugar levels are well-controlled. The average blood sugar corresponding to this range is below 117 mg/dL (6.5 mmol/L).
Continue maintaining a healthy diet, regular exercise, and routine health check-ups.
Your blood sugar is higher than normal but not yet in the diabetes range. Average blood sugar: 117–137 mg/dL (6.5–7.6 mmol/L).
Without intervention, prediabetes often progresses to type 2 diabetes within 5-10 years. Lifestyle changes can reduce this risk by up to 58%.
Your blood sugar indicates diabetes. Average blood sugar: 140 mg/dL (7.8 mmol/L) or higher.
A second confirmatory test is usually performed. Your healthcare provider will develop a treatment plan which may include medication, lifestyle changes, and regular monitoring.
Target A1C Levels by Age
A1C targets vary based on age, diabetes type, and individual health status. The following are general guidelines from major medical organizations:
Children & Adolescents (under 18)
The International Society for Pediatric and Adolescent Diabetes (ISPAD) recommends an A1C target of less than 7.5% for children with type 1 diabetes. Avoiding severe hypoglycemia is a priority, especially in young children whose brains are still developing.
Adults (18–64)
The ADA recommends a general target of less than 7% for most non-pregnant adults with diabetes. The AACE suggests a more stringent target of 6.5% or lower if it can be achieved without significant hypoglycemia. Individualization is key.
Older Adults (65+)
Less stringent A1C targets (less than 8%) may be appropriate for older adults with multiple chronic conditions, limited life expectancy, or a history of severe hypoglycemia. The goal is to balance blood sugar control with quality of life and safety.
Pregnant Women
For women planning pregnancy, an A1C of less than 6% is recommended before conception. During pregnancy, a target of 6–6.5% is suggested to minimize risks to both mother and baby. Gestational diabetes is managed with similar targets.
What Can Affect A1C Accuracy?
While A1C is a reliable test, several conditions can cause results that don't accurately reflect average blood sugar:
- Iron deficiency anemia — Can falsely elevate A1C results. Treating the anemia often normalizes A1C.
- Hemoglobin variants — Sickle cell trait (HbS), thalassemia, and other hemoglobinopathies can interfere with certain A1C assay methods, giving falsely high or low results.
- Pregnancy — Increased red blood cell turnover and iron changes during pregnancy can affect A1C accuracy, which is why fasting and postprandial glucose monitoring is often preferred.
- Blood loss or transfusion — Recent significant blood loss or transfusion changes the red blood cell population, affecting the 2-3 month average that A1C represents.
- Chronic kidney disease — Can cause both falsely high and low A1C depending on the stage and treatment (dialysis).
- Certain medications — High-dose vitamin C or E, dapsone, and some HIV medications can interfere with A1C results.
If your A1C results seem inconsistent with your home glucose readings, discuss alternative tests like fructosamine or glycated albumin with your healthcare provider.
It is also worth noting that some individuals are naturally "high glycators" or "low glycators," meaning their hemoglobin binds glucose at a faster or slower rate than average. For these people, their A1C result may not accurately reflect the average glucose shown by a CGM or frequent finger-stick testing. This is a recognized biological variation, not a laboratory error or test malfunction. If your CGM average glucose and your lab A1C seem consistently mismatched, discuss this possibility with your doctor, who may recommend using GMI (Glucose Management Indicator) or time-in-range data alongside A1C for a more complete picture of your glucose control.
Related Calculators & Resources
Frequently Asked Questions
What is considered a normal A1C?
A normal A1C is below 5.7%, which corresponds to an estimated average glucose below 117 mg/dL (6.5 mmol/L). This means your blood sugar regulation is functioning normally.
Is an A1C of 5.7% normal?
An A1C of 5.7% is at the borderline between normal and prediabetes. The ADA classifies 5.7% as the beginning of the prediabetes range. If your A1C is exactly 5.7%, your doctor may recommend lifestyle modifications and more frequent monitoring.
Does A1C change with age?
A1C levels tend to increase slightly with age, even in people without diabetes. Some studies suggest that A1C may be about 0.1% higher for each decade of age. This is why some guidelines allow slightly higher A1C targets for older adults.
What can make A1C results inaccurate?
Several factors can affect A1C accuracy: iron deficiency anemia (falsely high), hemoglobin variants like sickle cell trait, recent blood loss or transfusion, chronic kidney or liver disease, pregnancy, and certain medications. If you have these conditions, discuss alternative tests with your doctor.